A wireless communication device may include a receiver to receive signals over a communication channel. The receiver may operate at an acquisition mode of operation, e.g., to detect (i.e., acquire) communication packets over the communication channel. After acquiring a communication packet, the receiver may switch to a receive mode of operation to receive the acquired packet.
In some cases, the receiver may misidentify interference signals, e.g., noise signals, as communication packets. Consequently, the receiver may switch to the receive mode of operation and receive the noise signals (“noise-related packets”) as communication packets.
After receiving the packet, the communication device may perform an error check, for example, a Cyclic Redundancy Check (CRC), to determine whether the received packet is erroneous. However, a relatively long time period, e.g., approximately 1 millisecond, may be invested in receiving the packet before the received packet may be determined to be erroneous. During this time period, the receiver may not be able to acquire another packet. Consequently, the throughput of the communication device may decrease, often significantly, for example, in the vicinity of a persistent noise source.
In some systems, the communication device may perform a parity check to determine whether the acquired packet is erroneous, e.g., based on a Physical Layer Convergence Procedure (PLCP) header of the acquired packet. A parity checker of the communication device may calculate a parity check value of the PLCP header and may compare the calculated parity check value to a parity check bit of the PLCP header. A mismatch between the calculated parity check value and the parity check bit may indicate the acquired packet is an erroneous packet. In such a case, the receiver may switch back to the acquisition mode of operation, e.g., before the entire packet is received. However, since the parity check bit has only two possible values, e.g., zero or one, there may be a probability of up to 50% that an acquired packet passing the parity check is actually a noise-related packet.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity or several physical components included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function.